/Engine/Source/Runtime/Engine/Classes/Engine/PlatformInterfaceBase.h
Check for certain exec commands that map to the various subclasses (it will only get/create the singleton if the first bit of the exec command matches a one of the special strings, like "ad" for ad manager)
static bool StaticExec ( const TCHAR * Cmd, [FOutputDevice](API\Runtime\Core\Misc\FOutputDevice) & Ar )